(a) Technical Field
The present disclosure relates to a low noise tire. More particularly, it relates to a low noise tire composed of a structure in which a sound-absorbing material containing a polypropylene melt-blown fiber is adhered to a sealant layer at the inside surface of the inner liner of the tire.
(b) Background Art
Recently, as the power performance of vehicles has been enhanced, studies on enhancing performance of the tire have been actively conducted. The tires are the one part of the vehicle that only have contact with the ground surface among vehicle parts, and are an important part which significantly affects power delivery, direction change, fuel efficiency, and brake performance of a vehicle.
Such a tire is closely associated with noise and vibration performance generated during the driving as well as basic power performance. In particular, a main cause for road noise in a low frequency region of 200 to 250 Hz is a resonance sound generated as tires are driven, and an efficient method for reducing the resonance sound is most effective when the resonance sound is removed directly from tires. Since tires are mounted to the vehicle while being coupled to the vehicle wheels, the tire and wheel form a sealed structure, and are filled with air in a highly pressurized state of 30 to 40 psi. The sealed tire in the highly pressurized state is rotated by the engine output, generating a resonance sound due to the rotational force at a high speed.
In the related art, Korean Patent Application Laid-Open No. 2013-0022893 discloses a pneumatic tire in which a porous sound-absorbing material is adhered to a sealant layer including a butyl rubber, polyisobutylene, an inorganic additive and a vulcanizing agent on the inside surface, but has a limitation on minimizing the generation of sound by reducing the resonance sound.
Further, Japanese Patent Application Laid-Open No. 2010-201997 discloses a tire having a sound absorbing layer which is configured with nonwoven fabric fibers of which are oriented in the thickness direction on the inner surface of the tire, but the tire may have poor appearance and durability problems due to the nonwoven fabric.
Recently, in order to eliminate the problem of resonance sound, tires have been produced, in which a foamed urethane foam is adhered to the tire by using a double-coated tape and a toluene-based primer. Here, as a representative material for a sound-absorbing material for a tire universally used, a material processed by foaming polyurethane (PU) is used. However, a sound-absorbing material composed of polyurethane has a problem in that the material is hydrolyzed under moisture and high temperature conditions, and as a result, the NVH functions deteriorate due to breakage and damage of the sound-absorbing material. In addition, there may occur a problem that physical properties and the life-span of the tire deteriorate due to a decrease in adhesive force of the adhesive while driving in the field. Therefore, there is a need for studies which minimize the generation of noise and improve the performance of tires.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.